Card Set Information

2012-11-12 18:15:10
ANAT390 GI System

ANAT390 Lecture 27 GI System 2
Show Answers:

  1. What is the purpose of the stomach?
    The stomach initiates digestion of food.
  2. Describe the gastric mucosa.
    • Simple columnar epithelium
    • Gastric glands are found in the depressions of the epithelium
    • Apical/lumenal spithelial secretions are mucous, acid, and proteases
    • Basal secretions are hormones and paracrine factors
  3. Define rugae.
    Transient gastric mucosal folds
  4. How many sphincters are in the stomach and where are they located?
    • Lower Esophageal/Cardiac Sphincter
    • Pyloric Sphincter
  5. What are the six type of cells in the gastric epithelium?
    • surface lining cell
    • regenerative cell
    • mucous neck cell
    • oxyntic (parietal cell)
    • zymogenic (chief) cell
    • enteroendocrine cell
  6. What is the function of chief cells?
    • Secrete zymogens apically into the lumen
    • Zymogens are activated by acid hydrolysis 
  7. What is the function of enteroendocrine cells?
    • Secrete hormones and paracrine factors
    • ie. Vasoactive Intestinal Peptide (VIP) - increases peristalsis of intestines
    • Gastrin - increases parietal cell acid secretion in stomach and relaxes pyloric sphincter
  8. What is the function of the small intestine?
    • Digestive- via enzymes delivered to the small intestine from the pancreas
    • Absorptive - via mucosa
  9. Describe the layers of the small intestine.
    • Epithelium - simple columnar, absorptive cells (Enterocytes), protective mucous secreting goblet cells, anti-bacterial paneth cells
    • Lamina Propria - Loose connective tissue, many vascular capillaries and lymphatic capillaries (central lacteals), prominent MALT
    • Submucosa - alkaline, mucous secreting 'Brunner's Glands' 
  10. How does the small intestine increase its absorptive surface area?
    • Makes use of microvilli (projections) and crypts/glands (depressions)
    • Microvilli contain many channels/transporters in plasma membranes 
  11. What are paneth cells?
    • Contain apical pink/eosinophilic granules
    • Secrete antibacterial lysosymes
    • Can become phagocytic, antigen-presenting cells
  12. What are Brunner's Glands?
    • Exocrine, secretory glands found in the submucosa all the way to the muscularis mucosa
    • Secrete protective, alkaline mucous which is protective of acid produced by the stomach
    • Ducts empty into base of intestinal crypts
  13. Describe the MALT in the small intestine.
    • B and T Cell aggregates (no CT capsule)
    • Can be activated by Paneth cell-mediated Antigen Presentation
    • Pale germinal centers indicate B Cell Activation
    • Increase in numbers towards the terminal end of the small intestine
    • In appendix (at small/large intestinal junction, fill entire lamina propria)
  14. Describe the layers of the large intestine.
    • Mucosa: Absorptive (especially for H2O), crypts/glands present, but no villi
    • Epithelium:  Simple columnar; enterocytes with high number of goblet cells
    • Submucosa: no brunner's glands
    • M. Externa: Terminal thickenings= Anal Sphincters, smooth muscle internally and skeletal muscle externally
  15. Describe the junction of the terminal portion of colon with the anus.
    • There is an epithelial transition between columnar epithelium and stratified squamous epithelium.
    • The pectinate line is the interface between endoderm and ectoderm. 
    • Metaplasia can occur here as well.